The Battle of Camlann is best known as the final battle of King Arthur, where he either died in battle, or was fatally wounded. As the surviving accounts of this battle are all generally little more than legend or myth (and all versions exhibit traces of folklore), some historians doubt this battle even took place.
The earliest known reference to this battle is the entry in the Annales Cambriae for the year 537: Gueith camlann in qua Arthur et Medraut corruerunt _ "Battle of Camlann in which Arthur and Medraut (Mordred) perished". Later accounts of this battle are in Geoffrey of Monmouth's Historia Regum Britanniae, and in the 13th century Welsh tale, "The Dream of Rhonabwy."
A possible site is Queen Camel in Somerset which is close to the hill fort near South Cadbury (identified by some with King Arthur's Camelot), where the River Cam flows beneath Camel Hill and Annis Hill. However, a number of other identifications have been offered, including Birdoswald near Hadrian's Wall (Latin "Camboglana"), the River Camel along the border of Cornwall, and the River Camlann in Eifionydd in Wales.
The entry for a year that may be 539 reads, "the strife of Camlann in which Arthur and Merdraut fell." No mention of villainy or opposition between the two is made.
In the triads, Camlann is one of the "Three Futile Battles," the result of a tragic, bloody feud.
While Camlann may have actually happened, it is impossible to place not only the location but a real Arthur in the battle.